An electrode active material is used for an electrode in a non-aqueous secondary battery such as a lithium secondary battery. The lithium secondary battery has already been put into practical use as a small-sized power supply for use in portable telephones, notebook personal computers, etc., and has also been tried to be applied to a middle-sized to large-sized power supply for use in automobiles, power storage, etc.
As a conventional electrode active material, Patent Document 1 has disclosed an electrode active material obtained by mixing two kinds of lithium mixed metal oxide powders having a BET specific surface area of 2.0 m2/g or less, the powder having a layered rock-salt type crystal structure.